In recent years, a high-power laser beam machine with a laser beam power exceeding several kilowatts has been widespread, and used in various production sites. Especially, a laser beam machine of a fiber transmission type has been widespread remarkably. A high-power laser beam is guided to a fiber and transmitted, and then used for processing.
To obtain a high-power laser beam, a laser oscillator has laser beams emitted from plural laser light sources spatially overlap one another to obtain a high-power laser beam, rather than a method of increasing power of a laser oscillator itself, serving as a light source for emitting a laser beam, i.e., increasing power of a single laser light source. A fiber coupling device allows the spatially overlapping laser beams are guided to a fiber and transmitted, and then used for processing (see, e.g., PTL 1).
A fiber coupling device that is used when a laser light source is changed or replaced is known (see, e.g., PTL 2).
FIG. 4 is a cross-sectional view of conventional fiber coupling device 100. Fiber coupling device 100 is attached to a laser beam outlet of a laser oscillator constituted by plural laser light sources. Converging lens 142 included in fiber coupling device 100 is adjustably held via lens cylinder 140 with adjustment screw 146. Process fiber 122 is adjustably held via connector cylinder 160 and connector 164 with adjustment screw 146. Connector cylinder 160 includes cover glass 120 facing connector 164.
An operation of fiber coupling device 100 will be described below. Plural laser beams emitted from plural laser oscillators enter fiber coupling device 100. The laser beams are converged through converging lens 142 and guided to process fiber 122. At that moment, converging lens 142 is adjusted with adjustment screw 146, and process fiber 122 is adjusted with adjustment screw 146.
Only a specified laser light source among the plural laser light sources is replaced by the following method. After connector cylinder 160 is detached from fiber coupling device 100, fiber coupling device 100 is detached from plural laser oscillators, and then, lens cylinder 140 is detached. After that, the specified laser light source is replaced. Alternatively, after fiber coupling device 100 is detached from plural laser oscillators, lens cylinder 140 is detached. Then, the specified laser light source is replaced. Subsequently, connector cylinder 160 is attached to fiber coupling device 100 again, and then, fiber coupling device 100 is attached to the laser oscillators after lens cylinder 140 is returned back to fiber coupling device 100. Alternatively, fiber coupling device 100 is attached to the laser oscillators after lens cylinder 140 is returned back to fiber coupling device 100. After that, converging lens 142 or process fiber 122 is adjusted to operate.